Back when Bluetooth was new, the alternative for wirelessly sharing data between mobile devices like phones was infrared.

IR was exceptionally slow, required line-of-sight and even at the time, felt like a shitty solution. So even though the early implementations of Bluetooth also left a lot to be desired (battery hungry, insecure, and also slow), it was still a massive improvement on what came before.

Wireless USB wasn’t a significant enough improvement to Bluetooth given that BT was already ubiquitous by that point, but also cheap and (by that point) battery efficient now too.